Cable clamp



Y rJuly 4, 1933- J. K. osTRANDER CABLE CLAMP original Filed Jan.

PatentedV July 4',` 1933,

UNITED. ASTATES JOHN K. OSTRANDER, for PHILADELPHIA, rinviasYLvAixIAy fCABLE CLAMP Application flied January 12'1931, Aserial No. 5:18307.Renewed May 18, 1933.

One object of the invention` is to provide.

aV cable-'gripping clamp in which the gripping force is automaticallyregulated by the Weight of thatportion of the cable supported by theindividual clamp. i

Another robject of the invention is Vto provide a cablefsupporting clampof thestated character having an automatic safety feature, in thatincrease of the load applied to 4the cla-mp through the cable to apredetermined maXimum results in a partial release of the gripping force.of the clamp, permit- 5520 ting longitudinal slippage' 0f @he Cable.throughthe clamp. A n v 'Another object of the invention is to providea clamp in which any upward movement vof the cable in the supported parthas the 25 eifectof temporarily releasing the grip,'for

a purpose hereinafter fully fset forth. n Still another object of` theinvention is to Vprovide a cable-gripping clamp having certain desirableself-adjusting' characteristics,

30 as hereinafter set forth.

' The invention further resides lin certaindesirable structural featuresand-details hereinafter'described and illustrated in the at taeheddrawing, in which:' v,

Figure 1 is an end elevation of ai clamp made in accordance with myinvention, and

Fig. 2 is a sidel elevational view of the clamp. A Q

With reference tothe drawing, the clamp in a preferred form comprises apairof ,arms

1 and 2`joined together attheir lower ends by means in the presentinstance of a pair of bolts 3, 3, said arms being provided with alignedopenings 1 and 5, respectively, which 5 receivethe trunnions 6 and 7respectively,

of a pair of segmental cable-grippingelementsV 8 and 9, adaptedinassembly and as illustrated'in Fig. 1 to lengage the oppositel sides vofav cable 10..From a point above the openingsl the arms land 2 liareoutwardly away 4from each other, as indicated at 11, and each arm at itsupper extremity is provided with an opening for reception of'a pinf1'2,these pins yfunctioningto secure to each of said arms afpair of links,13, 13 and'14, l141, respectively. These pairs of links which`preferably occupy positions onroppo'site sides of their respectiveassociated arms 1 and 2 converge upwardly and are pivotally connectedthrough the medium ofV a pinv 15 to a. depending arm 16.v This arm isadapted to be securedto a bank of insulators which maybe supported on orsuspended from any suitable supporting structure.

The retaining bolts 3, 3 are more orle'ss free 65 'in the arms 1 and 2to permit a certain limited adjustability of the arms with respect toeach other.y The construction described thereby produces through the'medium of the arms 1 and 2, the bolts 3 andthe links 13 and 14; a 70toggle effect wherein the weight 'of the cable 10 tends to draw theupper ends of the arms 1 and 2 together. and consequently the 'elements8 and 9 forcibly against'the opposite sides'of the cable. The` grippingforce of 75 the .elements 8 and 9 upon'the cable, therefore, variesdirectly with the load applied to theclamp through the cable. It will benoted,

however, that the load constituted by the cable 10 vhas a tendency tocause the upper portions 11 ofthe arms 1 and 2 tok straighten out intothe positions illustrated by the broken linesin Fig, 1. By a judiciousproportioning off-the said arms, it is possible to introduce into thedevice a critical maximum-loadsustaining factor whereby at a givenmaXimuni load the said arms 1 and 2 will flex into positionsapproximately .as shown' in broken lines. y This has the effectofvelongating the toggle by increasing the angle at the toggle joint,and thereby correspondingly reduces the toggle action andthe effectivegripping force of the elements 8 and 9 upon the clamp. When soconstructed, the effective gripfof the vclamp upon the cablewillincrease inl direct ratio with the increase of the load applied throughthe cable to a predeterminedmaximum, at-which point the gripping forceis automatically decreased a predetermined eX- n tent, this reductioninthe grippingaction '100 being sufficient to permit longitudinalslippagel of the cable between the gripping jaws 8 and 9 in the eventthat the load at opposite sides of the said jaws is unbalanced.

As a practical application of this principle, it will be understood thathigh tension and similar vcables are commonly-supported on l high towersplaced atv reasonable intervals,

and that when oneof the transmission lines parts between any two towers,the normally balanced strain upon the adj acent towers is immediatelyunbalanced. In some instances,

these towers are made sufficiently streng to withstand these,Vunbalanced strains, but this involves a relatively high expense in thecon# struction of the towers, and for that reason is undesirable. Withthe' present device, the

supporting towers may bebuilt to withstand l 'a predetermined unbalancedstrain, andthe varmsl and 2 of the y'clanfip may` be so con-'structedthat they willftle-X under acorre- .spending load. Under thesecircumstances, :the clamp Vwill retainits normal securergrip uponithecable under allfco'nditions except when the load upon the clampapproaches the vmaximum sustaining load yof the tower,whereupon.thefclamp will permit slippage or the cable,vinsuring asufficient balancing kof the load upon the tower tov prevent damage.tothe latter. j i Y T g '.Ink addition tothe action described above,the device operates to relieve the towersot some of the shock resultingfrom therecnil of the loose ends of the cable at opposite sides of abreak. The supported cables' are necessarilyv under a considerabletension which when a break occurs result-s in a heavy vrecoil of thewireat each side of the break. Where, as has previously been thepractice, the cable is gripped rigidly by the clamps, vtheatoredescribed reaction is taken up entirely by the l kadj acent towerswhich must be built Vto withstand thisL sudden heavyunbalanced load. It,s has been `found that theinitial recoil of the `wires has theeiiect ofactually elevating the vwirewhere it is supported at the adjacent jaws 8and `9, not sufficiently, however, to

entirely disengage the jaws fromthe cable. j

In addition to the automatic safety features described above, myinvention provides a de.-

vicey of relative simplicity and low cost of manufacture which at thesame time ishighly efficient in its intended function; j By mounting theclamping j awsupon trunnions as de,- scribed, the awsautomaticallyadjust them,.-

selves to the normal position of the cable and thereby avoid unduestrains upon the .clamp Y or upon the cable. The invention also aiifordsby simple means an adjustment of the clamp to Iit cables of differentdiameters, this being accomplished by a tightening or loosening of thebolts 3 jaws Bland. 9L having an internal curvature corresponding to-thecircumferential'dimenf sions of the particular cable to be supported'.

-ture from the invention. I -c'l'aim :V

the arms togethenadjacent their lower` ends,

,suspensionfmeansfconnected to said arms .and

There may bemodiication without deparv V1. Acarble clamp comprisingapair of up! "wardly divergrngarms, *means-'fr securing 'andby use ofclamping sov permitting movements ofthe upper, ends ofi 'di' the armstoward each other, and means fintermediate `v the endsfof saidiarms forengaging opposite sides of a cable, the diverging portions of'saidfarrns being [so constructed 'and' arrai'iged v"t ieX .inwardlywhen; thefsaid load Y exceedsi .predetermined lmaximum whereby thegripping `force of saidarins upon the cable is automatically decreased.

2. In a cable-supportingclamp, ,the` i, bination with a pair'of''.L'ipwardly.diverging-V arms,of a pairof oppositely arrangedcableengaging j clamps, respectivelyV i pivotally mounted infsaid armson axes' transverse to the direction' of the supported `cable, meansforlpivotally connecting the said armsat a point below{thefgsaidc'ablefgrip'ping`y jaws, the upper ends of said arms beingadjustablysecured to a supportingv structure whereby `the weight ofthe cable tends,tn drawfthe Viippcl. ends of saidarmstogether.,

3. Acable clamp comprising afpair'ofin- `,terconnected clampingarms,andmeans for suspending the arms so thatfthey tend to draw togetherupon,I an interposed, cable, said arms being constructed' to bend undera prede- A l term'ined4 abnormal Htorce to decrease the clampingpressure thereof upon .the cable'. j

4. In a snepension clampvfor cables,- vthe combination' `with'a pairyotarms havingim `termediate'the ends thereof opposedcable gripping jaws,"of means .for'pivotallysecuringsaid arms togetheriat a point below saidjaws, said` arms comprising divergent portions above the jaws, meansfo'rsuspending the arms from a supporting structure wherebythe weight :of asupported `cable inconl junction with.l the "divergent arms tends todraw: the jaws` iirmly'against the cable, and saidljdivergent' partsbeing jconstructed to vb'endtoward'-1each other under 'a .predeterminedabnormal load to thereby decreasel the clamping'pressureon'the'cable., i

toggle suspension ron said Y, elements tending to elongateA underyl,weicht[of ,the cable, said toggledeteneiensthe pressure "Of @hesse u`5. lua 'cablefsuprertns .Clamrfth combin'ation ywithcable-gripping.elements,. oita toggles relieving a portion of theclamping pressure thereof upon the cable.

.7.l In a cable clamp, the combination With cable-gripping elements, ofmeans including a cable-supporting member constructed, to distort undera predetermined abnormalload forreducing the gripping force on the cableof said elements when the load imposed'by the cable on the clamp reachesa predetermined maximum.,

JOHN K. OSTRANDER.

vso

